A known exercise device including a weight body structure is disclosed in EP1867365. In the arrangement disclosed in this prior art document an inner weight section or core body of cast iron is cast about an axial securing sleeve. The sleeve provides an interference fit between the weight body and the end of a bar handle. An outer skin of rubber or polyurethane is subsequently molded around the exterior of the cast iron section. EP 867365 describes how an arrangement including a low grade cast iron core body cast around an axial securing sleeve can provide an improved arrangement. The present invention addresses other issues.
Typically the cast iron used for weight bodies is of low grade or quality enabling the manufactured weight structures to be priced sufficiently economically. Due to the materials used, the weight tolerances for these low to mid-range free weight products are wide, and not as tight as those used in competition or high quality Olympic discs which are generally manufactured from steel, which provides better weight accuracy but is more expensive.
The processing of Cast Iron involves very high temperatures, which requires large amounts of energy and also requires the use of sand-based molding processes that are, by their nature, very dirty and unpleasant to use.
Also, the cost of transportation by ocean freight of weight based products over long distances is becoming more expensive and is not considered to be environmentally friendly where large tonnages are concerned. It is more ideal to manufacture as close to the end consumer as possible. However, in the case of Cast Iron based free weights this is often not possible because of the associated local high labor costs and the unpleasant nature of the process.
One additional requirement in the production of free-weights is the use of rubber (usually black) to cover the low grade Cast Iron so that in can be used in clean and user friendly environments, such as modern gyms or homes. The rubber based coverings are more tactile and will not damage equipment, delicate floorings, or furnishings in the way that metal products would. The process of coating the free-weights in rubber also consumes energy and is a dirty and unpleasant process.
Therefore, for reasons identified above, it would be more desirable if a cleaner process, requiring very little energy and providing greater weight accuracy could be utilized. Such a process would allow for reduced costs and for the manufacturing plant to be brought closer the end user.